The Zagreb County Court handed down a suspended sentence of two years in prison for Knezevic in November last year.
The Supreme Court passed the ruling on 14 July this year and made it public on Wednesday after all the parties received copies of it.
The Supreme Court found that the lower court made a mistake when it ruled that an act of unauthorised consulting with which Nevenka Tudjman was charged, was not a criminal act of abuse of official duty.
The Supreme Court ordered a retrial in that segment of the indictment.
USKOK alleges that Nevenka Tudjman interceded with the then science minister, Ivica Kostovic, and his deputy Nikola Ruzinski so that the Science Ministry would enter into a contract with Knezevic for the installment of telephone switchboards at colleges. In return, Knezevic gave her kickbacks, USKOK claims.
The County Court wrongly established that the abuse of office was not at work.
The Supreme Court explained that it is beyond any doubt that a minister and his deputy are persons in office and that the lower court made a mistake when it ruled them out of the categories of performance of official duties, including the conclusion of a contract on consulting.
The Supreme Court also ruled that the County Court substantially violated provisions of the criminal proceedings while failing to mention in its ruling crucial facts about a criminal act such as the use of official influence which Nevenka Tudjman had exerted, her services in making an official agreement which should not have been reached and having benefits from that.
The Supreme Court turned down other parts of the USKOK appeal describing them as groundless, and it thus upheld the rest of theruling made by the lower court.